Financial Instruments And Risk Management (Balance Sheet Classification And Fair Value Of Derivative Instruments) (Details) - Currency Forward Contracts [Member] - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Prepaid Expenses And Other Current Assets [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 4,729	$ 11,855	$ 16,603
Prepaid Expenses And Other Current Assets [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	2,211	2,146	1,857
Other Noncurrent Assets [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	3,454	4,159	4,830
Accrued Liabilities [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	2,034	1,313	201
Accrued Liabilities [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	381	953	320
Other Long Term Liabilities [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 1,186	$ 768	$ 109